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Concise Construction of the ACDE Ring System of Calyciphylline A Type Alkaloids by a [5+2] Cycloaddition
Author(s) -
Nakamura Hugh,
Kawakami Manami,
Tsukano Chihiro,
Takemoto Yoshiji
Publication year - 2019
Publication title -
chemistry – a european journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.687
H-Index - 242
eISSN - 1521-3765
pISSN - 0947-6539
DOI - 10.1002/chem.201901690
Subject(s) - ring (chemistry) , cycloaddition , olefin fiber , intramolecular force , chemistry , vicinal , carbon skeleton , wittig reaction , stereochemistry , skeleton (computer programming) , medicinal chemistry , organic chemistry , catalysis , computer science , programming language
A concise route for construction of the ACDE ring skeleton in calyciphylline A type alkaloids was developed using an intramolecular [5+2] cycloaddition reaction of an oxidopyrylium species bearing a tetrasubstituted olefin. Key to the success of this reaction was the combination of acid and base, which accelerated the construction of this skeleton containing a spiro ring and vicinal quaternary carbon centers. The resultant tricyclic ADE ring compound was converted to an ACDE ring model through C−H oxidation and an aza‐Wittig reaction.